The present invention relates to an ink jet recording apparatus, an ink jet head cartridge mountable thereto and an ink container mountable thereto.
In a type of ink jet recording apparatus wherein ink is deposited on the recording material to effect the recording, an ink cartridge containing a predetermined quantity of the ink is exchangeable to replenish the ink jet recording apparatus with the ink. When the cost of the ink jet recording head is low, a head-container cartridge is used wherein the recording head and the ink container having a capacity of a predetermined quantity of the ink are constructed as a unit. In the latter type, the recording head is exchanged with fresh one each time after a predetermined amount of recording is effected. Therefore, the good recording quality can be maintained. Even if a trouble leading degraded recording quality occurred, the inoperable time period could be reduced, because the ink jet recording head which is the key element could be easily exchanged. In addition, the liability of introduction of foreign matter attributable to the replenishment of the ink can be avoided.
In such a head-container cartridge, the ink container containing the ink to be supplied to the ink ejector is provided, which is required to satisfy the following:
(1) The ink does not leak out;
(2) The ink does not evaporate;
(3) It contains a predetermined quantity of the ink and supplies it to the ejector; and
(4) It does not obstruct the ink ejection by the ejector.
In order to practically satisfy the above functional requirements, an ink container of an ink bag type or a sponge type are known. In the latter type, an ink absorbing material is disposed in the ink container, so that the ink in the ejector is under the vacuum.
The ink bag type involves the problem regarding the above requirement (4). More particularly, in order to avoid the influence by the static head of the ink to the ejector, the relative positional relation between the recording head and the ink container is more or less limited. In addition, the ink bag should be protected by an outside casing for the purpose of easy handling, which results in the cost increase.
The sponge type is free from the influence to the ejection by the static head of the ink.
Referring first to FIG. 1, there is shown a perspective view of an ink jet head cartridge of this type. The cartridge includes an ink container 160, an ink jet recording head mounted to the ink container 160, porous material 162 in the ink containing portion 160a. The porous material 162 is filled with the ink. The ink is supplied to the ink jet recording head 164 by way of an integrating passage not shown.
Ejection outlets 163 of the ink jet recording head 164 receive image signals from the main assembly of the apparatus to eject the ink droplet onto a recording material. A connector 165 establishes electric connection between the main assembly and the recording head.
A small chamber 160c is formed at a part of the container 160. It communicates with the ink containing portion 160a in the container through a connecting groove 160b. An air venting hole 160d is formed in a part of the small chamber. Following the ink ejection for the image recording, the air is introduced through the air venting hole 160d. A cover 161 seals the ink containing portion 160a and the small chamber 160c. The ink jet cartridge described above is normally positioned in use with the recording head 164 at the bottom, and therefore, the air venting hole 160d at the top. Accordingly, the ink does not leak out of the cartridge.
The air venting hole is provided to compensate the pressure change due to the consumption of the ink in the ink container or due to the temperature change of the air in the ink container, by communication between the inside and outside of the container. However, in the conventional ink container, the ink is easily evaporated through the air venting hole (requirement (2)). The ink evaporates with time with the result of following problems.
For example, water ink which is widely used from the standpoint of safety, is generally constituted by water, dye and non-volatile solvent. With the evaporation, and therefore, reduction of the volatile contents such as water, decomposition of the ink significantly changes to such an extent that the recording property such as the fixing property and the image density is influenced and that the ejectors are clogged by the increase of the ink viscosity. In addition, usable quantity of the ink decreases so that it is not economical. It will be understood that the problems arising from the evaporation are significant particularly in the case of the ink container having a smaller capacity.
When the cartridge of the above-described example is left with the air venting hole at the bottom as shown in FIG. 2, or it is left with its horizontal position, the ink in the container gradually lowers due to the ambient temperature change or the like. Then, an ink layer is formed in the porous material 162 at the bottom at the side where the air venting communication groove is formed, and on the other hand, an air layer is formed at the top where the communication passage with the recording head is formed. If the temperature rises with this state, the inside pressure increases by the expansion of the air remaining in the container, so that the ink A is pushed to the outside through the communication groove 160b and through the air venting hole 160d, and therefore., the ink leaks out.
In addition, when an impact is applied to the ink container which is positioned with its air venting hole at the bottom, the ink droplets come out through the communication groove 160b, and the ink leaks out of the container through the air venting hole 160d. 
When the ink jet cartridge described above is used with the ink ejection outlets 163 at the bottom as shown in FIG. 3, the ink remains in the region I which is indicated by the hatched lines and which is remote from the ink jet head 164 without being consumed.
It would be considered to incline the bottom 162b of the ink container in an attempt to prevent the ink from remaining. However, in order to accomplish this without reduction of the ink capacity, the ink jet recording head 164 has to be shifted downwardly toward the recording material. Then, the height of the entire apparatus 100 is increased, or the ink retaining performance decreases by the increase of the height of the ink absorbing material 162. Then, the ink is more easily leaked out through the ink ejection outlets 163.
Accordingly, it is a principal object of the present invention to provide an ink container, an ink jet recording head cartridge with the ink container as a unit and an ink jet recording apparatus using the same, wherein the evaporation of the ink can be suppressed for a long period of time, by which the good recording property can be stably maintained.
It is another object of the present invention to provide an ink container, an ink jet recording head with the ink container as a unit and an ink jet recording apparatus using the same wherein the leakage of the ink is effectively prevented.
It is a further object of the present invention to provide an ink container, an ink jet recording head cartridge with the ink container and an ink jet recording apparatus using the same, wherein the ink in the container is effectively supplied to the ink inlet of the recording head substantially without the ink remained in the container.
According to an aspect of the present invention, there is provided an ink jet head cartridge, comprising: a recording head for ejecting ink; an ink container for containing the ink to be supplied to said recording head; an air venting opening for communication between said container and ambience to allow supply of the ink from said container to said recording head; wherein said air venting opening is constituted by an outside opening and an inside opening and a passage connecting them, said passage has a length larger than a thickness of said ink container.
According to another aspect of the present invention, there is provided an ink jet recording apparatus, comprising: an ink jet head cartridge, including; a recording head for ejecting ink; an ink container for containing the ink to be supplied to said recording head; an air venting opening for communication between said container and ambience to allow supply of the ink from said container to said recording head; wherein said air venting opening is constituted by an outside opening and an inside opening and a passage connecting them, said passage has a length larger than a thickness of said ink container; said apparatus further comprising a carriage for movably supporting said cartridge.
According to a further aspect of the present invention, there is provided an ink container, comprising: an ink containing portion for containing ink; an opening for communicating between said ink containing portion and ambience; a tubular passage connecting the inside of said containing portion and said opening.
According to a further aspect of the present invention, there is provided an ink jet recording apparatus, comprising: an ink jet head unit having an ink passage provided with energy generating element for generating energy contributable to ejecting ink; an ink container, integrally formed as a unit with said ink jet head unit, having an ink containing portion for containing the ink to be supplied to said ink passage and having an opening for communication between an inside of said container and ambience; an air passage for communication between the inside of said ink containing portion to said opening; said ink jet head unit and said ink container constituting an ink jet head cartridge; and a member for mounting thereon said ink jet head cartridge.
According to a further aspect of the present invention, there is provided an ink jet head cartridge, comprising: a recording head for ejecting ink; an ink container for containing the ink to be supplied to said recording head; an ink absorbing material made of porous material or fibrous material in said ink container, wherein an inside of said ink container is in communication with ambience to permit supply of the ink from said ink container to said recording head; a small chamber in communication with said ink absorbing material substantially at a center of said ink container, said small chamber being provided with a projected opening in communication with the ambience.
According to a further aspect of the present invention, there is provided an ink jet recording apparatus, comprising: an ink jet head cartridge, including; a recording head for ejecting ink; an ink container for containing the ink to be supplied to said recording head; an ink absorbing material made of porous material or fibrous material in said ink container, wherein an inside of said ink container is in communication with ambience to permit supply of the ink from said ink container to said recording head; a small chamber in communication with said ink absorbing material substantially at a center of said ink container, said small chamber being provided with a projected opening in communication with the ambience; said apparatus further comprising a carriage for mounting thereon said ink jet head cartridge.
According to a further aspect of the present invention, there is provided an ink jet head cartridge, comprising: a recording head for ejecting ink; an ink container for containing the ink to be supplied to said recording head; an ink absorbing material made of porous or fibrous material in said ink container, wherein an inside of said ink container is communicated with ambience to permit supply of the ink from said ink container to said recording head, wherein said absorbing material has a higher density adjacent ink supply port for supporting the ink from said container to said recording head, and has a decreasing density away from the supply port; and a projection for providing the portion of the high density of said ink absorbing material by engagement with said ink absorbing material.
According to a further aspect of the present invention, there is provided an ink jet recording apparatus, comprising: an ink jet head cartridge, including; a recording head for ejecting ink; an ink container for containing the ink to be supplied to said recording head; an ink absorbing material made of porous or fibrous material in said ink container, wherein an inside of said ink container is communicated with ambience to permit supply of the ink from said ink container to said recording head, wherein said absorbing material has a higher density adjacent ink supply port for supporting the ink from said container to said recording head, and has a decreasing density away from the supply port; a projection for providing the portion of the high density of said ink absorbing material by engagement with said ink absorbing material; said apparatus further comprising a carriage for mounting said cartridge.
According to an embodiment of the present invention, a tubular communicating passage is extended from an inside space in the ink container of the ink jet head cartridge to the ambience, so that the space is opened to the ambience. Therefore, the evaporation of the ink in the container to the outside is impeded by the flow resistance provided by the long passage. Accordingly, by the suppression of the evaporation, the good and stabilized recording property can be maintained for a long period of time.
According to another embodiment, the ink container of the ink jet head cartridge as a small chamber, adjacent the center thereof, communicating with the absorbing material, and an air venting pipe projecting into the inside of the container and having a substantial length, by which when the ink jet head cartridge is left at any position, the leakage of the ink can be prevented.
According to this embodiment, the small chamber is formed adjacent the center of the ink container, and therefore, the strength of the ink container wall against deformation is enhanced, so that the ink jet cartridge has sufficient mechanical strength even if the container is made of thin walls.
According to a further embodiment of the present invention, the density of the ink absorbing material can be increased adjacent the ink supply port, so that the ink tends to gather toward the high density portion of the ink absorbing material by the capillary action, and therefore, even when the remaining amount of the ink becomes small, the ink is concentrated at the ink supply port side, by which substantially all the ink can be supplied to the ink jet recording head.